Water filter monitoring and indicating system

ABSTRACT

A method and apparatus for determining when a replaceable filter for a refrigerator needs replacing based on the volume of water passing through the water filter as determined by the product of the time that water has passed through the filter and the flow rate of an accessory being supplied the filtered water.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of U.S. patent applicationSer. No. 10/115,849, filed Apr. 3, 2002, which claims priority from U.S.patent application Ser. No. 09/605,776 filed Jun. 28, 2000, now U.S.Pat. No. 6,375,834, issued Apr. 23, 2002, which is a non-provisional ofprovisional application No. 60/141,693 filed Jun. 28, 1999, now expired.

BACKGROUND OF INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates to a refrigerator with a water filtrationsystem having a replaceable filter. More specifically, the inventionrelates to a device for indicating when the replaceable filter is readyto be replaced.

[0004] Description of the Related Art

[0005] Many refrigerators, and especially those using a side-by-sideconfiguration wherein the fresh food compartment is to the side of thefrozen food compartment, include integrated ice and water deliverysystems. Typically, such systems deliver water and ice through the doorof the frozen food compartment to a ice and water station recessed inthe door.

[0006] Examples of such systems can be seen in U.S. Pat. No. 5,907,958issued Jun. 1, 1999 to Coates , et al. and entitled “Refrigerator waterfilter”; U.S. Pat. No. 5,813,245 issued Sep. 29, 1998 to Coates , et al.and entitled “Pressure relief circuit for refrigerator contained waterfilter”; U.S. Pat. No. 5,715,699 issued Feb. 10, 1998 to Coates , et al.and entitled “Refrigerator water filter”; U.S. Pat. No. 5,707,518 issuedJan. 13, 1998 to Coates , et al. and entitled “Refrigerator waterfilter”; U.S. Pat. No. 5,135,645 issued Aug. 4, 1992 to Sklenak , et al.and entitled “Refrigerator water filter”; and U.S. Pat. No. 3,982,406issued Sep. 28, 1976 to Hanson , et al. and entitled “Refrigerator waterstorage and dispensing system with water filter”.

[0007] Increasingly such systems incorporate a filtration system with areplaceable filter element or cartridge so as to improve the quality ofthe ice and water delivered to the user of the refrigerator. Since thefilters must be periodically replaced to maintain the quality of thewater, various methods and apparatus could be used to notify the user ofthe need to change the filter. However, such many potential approacheswould be costly, complex and inflexible as to substitution of differenttypes of filters having different useful lives. Furthermore, in aneffort to such reduce cost, many such approaches fail to give the useradvance warning that the filter will soon need to replaced.

[0008] What is needed, therefore, is a filter monitoring and indicatingsystem that is flexible enough to permit its use with different types offilters yet doesn't add the cost of requiring an additional switch orsensor for detecting the type of filter being used.

[0009] What is further needed is an inexpensive filter monitoring andindicating system that not only informs the user that filter needs to bereplaced, but provides earlier warning that the filter will need to bereplaced soon and therefore a new filter needs to purchased.

SUMMARY OF INVENTION

[0010] In one aspect, the invention relates to a water supply system ina refrigerator comprising an ice maker and a water dispenser fordelivering filtered water from a water source to the ice maker and thewater dispenser. The water supply system comprises a replaceable filterthat is fluidly coupled to the ice maker and water dispenser by afiltered-water conduit and adapted to be coupled to a water source by awater source conduit. The replaceable filter has an inlet for receivingwater from the water source through the water source conduit and anoutlet for outputting filtered water to the ice maker and waterdispenser through the filtered-water conduit. The water supply systemfurther comprises a filter status unit that determines the status of thefilter based on the volume of the filtered water demanded by the icemaker and water dispenser.

[0011] The filter status unit comprises a water volume meter fordetermining the volume of filtered water outputted by the water filterfor each demand of water. A summing device is provided for maintainingan accumulated filtered-water volume based on the filtered-water volumedetermined by meter for each demand. An indicator signals when theaccumulated filtered-water volume reaches a threshold value indicativeof the need to replace the water filter.

[0012] The water supply system further includes a valve that that isfluidly connected to the filtered-water conduit to control the flow ofwater through the filtered-water conduit to one of the ice maker andwater dispenser. A second valve can be provided that is fluidlyconnected to the filtered-water conduit to control the flow of waterthrough the filtered-water conduit to the other of the ice maker andwater dispenser.

[0013] The water volume meter preferably comprises a timer and a dataprocessor. The timer determines the duration of each demand for water byeither the water filter or the water dispenser. The data processors usedfor calculating the filtered-water volume for each demand are based onthe duration of each demand. The data processor preferably includes amemory in which is stored a flow rate for least one of the ice maker andwater dispenser. The water volume can be calculated by the dataprocessor by determining the product of the duration and the flow rate.The memory can include a flow rate for each of the water filter and thewater dispenser. The data processor selects the proper flow ratedepending on which of the ice maker and the water dispenser is demandingwater.

[0014] A sensor can be provided to determine when the water is flowingfrom the water filter to the one of the ice maker and water dispenser.The sensor preferably includes an electrically actuated valve forcontrolling the flow of water from the water filter to the one of theice maker and water dispenser.

[0015] The timer preferably comprises a clock that is coupled to thedata processor. The data processor uses the clock to determine theelapsed time that water flows from the water filter to the one of theice maker and water dispenser as sensed by the sensor.

[0016] The summing device preferably comprises a portion of the memoryof a microprocessor in which is stored an accumulated filtered watervalue.

[0017] The indicator comprises at least one of a visual and audibleindicator. The indicator also preferably comprises a portion of theprocessor memory in which is stored a threshold value for the filter.The data processor compares the accumulated filtered water value to thethreshold value to determine the status of the filter and activates theat least one of the visual and audible indicators when thefiltered-water volume reaches the threshold value.

[0018] In another aspect, the invention relates to a refrigeratorcomprising a cabinet having a fresh food compartment with an open faceand a freezer compartment with an open face. A first door is mounted tothe cabinet for selectively closing the open face of the fresh foodcompartment. Similarly, a second door is mounted to the cabinet forselectively closing the open face of the freezer compartment. At leastone water-using accessory is provided with the refrigerator. Thereplaceable water filter having an inlet adapted to be fluidly connectedto a supply of household water and an outlet fluidly connected to the atleast one water-using accessory provides for the supply of filteredwater from the household supply to the at least one water-usingaccessory. A filter status unit is provided and indicates thereplacement status of the replaceable water filter based on theaccumulated volume of filtered water supplied by the replaceable waterfilter.

[0019] The water-using accessory is preferably one of a water dispenseror an ice maker. The at least one water-using accessory can include boththe water dispenser and ice maker. A valve can be provided for fluidlyconnecting at least one of the water dispenser and ice maker to thereplaceable filter. Similarly, a second valve can be provided forfluidly connecting the other of the at least one of the water dispenserand ice maker to the replaceable filter.

[0020] The filter status unit further comprises a timer that determinesthe duration of elapsed time that filtered water is supplied from thereplaceable filter. A filter-water volume calculator is also providedand calculates the filter-water volume based on the determined durationand the flow rate of the filtered water to the at least one water-usingaccessory. The timer preferably determines a duration for each supply ofthe filtered water to the at least one water-using accessory. Thefilter-water volume calculator calculates a corresponding filter-watervolume for each supply. The filter status unit can further comprise afiltered-water volume summing device that sums the calculatedfilter-water volumes for each supply to determine the accumulated volumeof filtered water.

[0021] The filter status unit can further comprise a microprocessorhaving a memory and a clock that is coupled to the microprocessor. Themicroprocessor and the clock form the timer to determine the duration ofeach supply. The microprocessor forms the filter-water volume calculatorby multiplying the duration by a flow rate stored in the memory. Themicroprocessor also forms the summing device by calculating and storingthe memory of the value corresponding to the accumulated volume offiltered water. If the refrigerator has multiple water-usingaccessories, a flow rate for each of the accessories can be stored inthe memory and the microprocessor selects the appropriate flow rate tocalculate the water volume supplied by the replaceable filter.

[0022] In yet another aspect, the invention relates to a filter statusunit for use in a refrigerator comprising at least one water-usingaccessory with a replaceable filter coupled to a water supply and awater supply system for delivering filtered water from the replaceablefilter to the at least one water-using accessory.

[0023] The filter status unit comprises a timer, filter-water volumecalculator, and a filtered-water volume summing device. The timerdetermines the duration of time that filtered water is supplied from thereplaceable filter to the at least one water-using appliance. Thefilter-water volume calculator calculates the filtered-water volumebased on the determined duration and the flow rate of the filtered waterto the at least one water-using accessory. The summing device maintainsan accumulated filtered-water volume based on the calculatedfiltered-water volume.

[0024] These and other advantages of the present invention will becomeapparent to those skilled in the art when the following detaileddescription of the preferred embodiment is read in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

[0025]FIG. 1 is a front perspective view of a refrigerator apparatushaving a water filtration and filter control and indicator systemembodying the present invention.

[0026]FIG. 2 is a schematic diagram of the ice and water assembly of therefrigerator apparatus of FIG. 1.

[0027]FIG. 3 is a fragmentary enlarged front view of the refrigeratorcontrol console of the refrigerator of FIG. 1.

[0028]FIG. 4 is a schematic electrical diagram illustrating theelectrical circuitry of the filter control and indicator system of FIG.1.

[0029]FIG. 5 is a flow chart illustrating the programming and logic ofthe filter control and indicator system of FIGS. 1 and 4 and moreparticularly illustrates the power-up and main subroutines of the filtercontrol and indicator system.

[0030]FIG. 6 is a flow chart illustrating the filter status subroutineof the main subroutine of FIG. 5.

[0031]FIG. 7 is a flow chart illustrating the indicator subroutine ofthe main subroutine of FIG. 5, including the indicator subroutine andthe diagnostics subroutine.

[0032]FIG. 8 is a flow chart illustrating the reset subroutine of themain subroutine of FIG. 5.

DETAILED DESCRIPTION

[0033] The Refrigerator

[0034] In the illustrative embodiment of the invention as shown in FIG.1 a refrigerator 10, comprising a side-by-side fresh food/freezerconfiguration, is provided having a cabinet 12 forming fresh foodcompartment 14 and freezer compartment 16.

[0035] The fresh food compartment 14 is provided with an access opening18 and a fresh food door 20 hingedly mounted to the cabinet 12 forselectively closing the access opening 18. The access opening 18 has aback wall 18 a, side walls 18 b and 18 c, top wall 18 d, and a bottomwall 18 e. The refrigerator 10 also has a partial front wall 22 disposedaround the perimeter of the access opening 18 parallel to andselectively engageable with the fresh food door 20 for sealing theaccess opening 18.

[0036] The fresh food compartment 14 is further provided with a light 24which is connected in series with a light switch 26. The light switch 26is a reciprocable switch actuated to selectively connect the light 24with a source of electrical power, not shown, when the door 20 is in anopen position and to disconnect the light 24 from the source ofelectrical power when the fresh food door 20 is in the closed position.In the preferred embodiment, the light switch is located in portion ofthe partial front wall 22 above the top wall 18 d of the access opening.

[0037] Similarly, the freezer compartment 16 is provided with an accessopening 28 and a freezer door 30 hingedly mounted to the cabinet 12 forselectively closing the access opening 28. The access opening 28 has aback wall 28 a, side walls 28 b and 28 c, top wall 28 d, and a bottomwall 28 e. The refrigerator 10 also has a partial front wall 32 disposedaround the perimeter of the access opening 28 parallel to andselectively engageable with the freezer door 30 for sealing the accessopening 28. The freezer compartment 14 is further provided with arocker-type light 34 which is connected in series with a light switch 36functionally similar to the light 24 and light switch 36 in the freshfood compartment 14.

[0038] As is further well known in the art, the refrigerator 10 isprovided with a water and ice supply system 40, shown schematically inFIG. 2 for delivering water from an external source 42 through a filter44 to an ice and water delivery system 46.

[0039] The filter 44 may be mounted to the refrigerator below the bottomwall 28 e of the access opening 28 and accessed for servicing byselective removal through an opening through the lowermost portion ofthe partial front wall 32, as shown in FIG. 1.

[0040] The ice and water delivery system 46 includes an ice makingassembly 48 mounted within the freezer compartment 16 and an ice andwater dispensing system 50 mounted in the freezer door 30.

[0041] The ice making assembly 48 is mounted to the inside surface ofthe back wall 28 a of the freezer compartment 16. The ice and waterdispensing system 50 is provided below the ice making assembly 48 forreceiving ice pieces therefrom as well as for receiving cool water froma water supply system 40. As shown in FIG. 2, the water and ice supplysystem 40 includes electrically operable water valves 52 and 54 forsupplying water, respectively, to the ice making assembly 48 and the iceand water dispensing system 50.

[0042] The ice and water dispensing system 50 includes an ice storagereceptacle or bin 56. When operated, the ice and water dispensing system50 transfers ice pieces from the ice storage receptacle or bin 56through the freezer door 30 whereby ice pieces may be dispensed througha conventional, forwardly exposed ice dispenser station or external iceservice area 58.

[0043] In the preferred embodiment of the present invention, arefrigerator control console 60 is defined on an upper portion of thepartial front wall 22 of the fresh food compartment 16 in the vicinityof the light switch 26. The refrigerator control console 60, which isshown integral with the front wall 22, includes a fresh food compartmenttemperature control switch 62, a freezer compartment temperature controlswitch 64, the light switch 26. In the vicinity of the light switch 26,the refrigerator control console also includes a filtration systemstatus indicator 66, described later in detail. The refrigerator controlconsole 60 further incorporates a consumer label 67 surrounding theswitch 26 and the indicator 66 on which is printed the following writtenmatter describing the operation of the filter 44 and the meaning of thestatus indicator 66: “EZ-CHANGE SIGNAL FILTER INDICATOR RESET Green =Good Filter Push the light switch Yellow = Order Filter 5 times in 10seconds to reset Red = Change Filter filter indicator to green.”

[0044] Components of the Water Filter Status Monitoring & IndicatingSystem

[0045] Referring now to the FIG. 4, the Refrigerator 10 includes a waterfilter status monitoring and indicating system 70. The water filterstatus monitoring and indicating system 70 includes a power supply 72comprising resistor 74, capacitors 76, 78 and 80 and diodes 82, 84, and86 in a conventional capacitive drop design with capacitor 76 as thecharge pump device, diode 82 as the rectifier. Diode 84 provides noisesuppression and functions as a clamping diode. Diode 86 (5.1V, 500 mW)is a zener diode used as a simple voltage regulator. Capacitor 80functions as the reservoir capacitor and capacitor 78 provides highfrequency bypass. Resistor 74 is critical to line surge performance ofthe overall circuit since it absorbs most of the pulse energy.

[0046] The water filter status monitoring and indicating system 70 hasan input connector 90 with three identical discrete digital inputs 94,96 and 98, respectively, for monitoring the light switch 26 and thewater valve electrical input of water valve 54 associated with the waterdispenser of the ice and water dispensing system 50, and the water valveelectrical input of water valve 52 associated with the ice makingapparatus 48. These inputs are designed for 120V (RMS) signals directlyfrom the monitored loads. Each of these inputs has an identical inputresistive divider network respectively comprised of pairs of resistors114 a, 114 b, 116 a, 116 b, 118 a and 118 b. Each resistor pair, 107,108 and 109, can also be viewed as a series device to limit current intothe microprocessor input pin, respectively, to the microprocessor device140 described later, and a shunt device to provide input pull-down to aknown state when the associated load is not activated.

[0047] The input connector 90 further has inputs 100 and 106respectively connected to the neutral and the hot lines of the AC powersupplied to the refrigerator 10. Inputs 92, 102 and 104 of the inputconnector 90 are not used.

[0048] The water filter status monitoring and indicating system 70 alsohas a power-on reset circuit 120 comprised of resistors 122, 124 and126, transistor 128, and capacitor 130. Resistors 122 and 126 set thereset threshold voltage and provide base drive for the transistor 128,and, in turn provides a pull-up voltage to master clear input 147.Resistor 124 is a passive pull-down to the master clear input 147 of themicroprocessor device 140 when VDD is low which establishes a validlogic low when VDD is below the threshold. Capacitor 130 providesfiltering for high frequency noise and transients.

[0049] The water filter status monitoring and indicating system 70further includes the filtration system status indicator 66, which in thepreferred embodiment consists of a bi-color device 110 containing a redLED die 132 and a green LED die 134.

[0050] The microprocessor device 140 provides all logic functionalityand memory. In addition to red and green, the color amber can beachieved by alternating resistors 136 and 138 by providing alternatingsignals from microprocessor output pins 144 and 146.

[0051] Microprocessor device 140 is preferably a Microchip PIC12CE518device, which contains 512 words of program ROM (implemented as OTPEPROM) and includes a 16 by 16 EEPROM.

[0052] The specifications of the preferred components of the waterfilter status monitoring and indicating system 70 are as follows:Component Reference numeral Specifications 72 74 76 78 80 82 84 86 88 9092 94 Resistor 114a Resistor 114b Resistor 116a Resistor 116b Resistor118a Resistor 118b 110 112 114 116 118 120 122 124 126 128 130 132 134136 138

[0053] Programming Logic of the Water Filter Status Monitoring &Indicating System

[0054]FIG. 5 through FIG. 8 illustrate the programming and logic of thewater filter status monitoring and indicating system 70 which isprogrammed into the microprocessor device 140. The Logic is intended toprovide programming for alternative models, such as an A modelrefrigerator a B model refrigerator or a C model refrigerator, eachhaving different functionality. The various models may have differentreplacement criteria for the filters depending on the gallon rating andthe useful life of the filter.

[0055] Referring to FIG. 5, when the power is first supplied to themicroprocessor device 140, a Power-up Subroutine 200 is initiated. Atstep 202, the microprocessor device reads the stored memory. At Step204, the microprocessor device 140 sends a signal to the indicator 66 toflash red if the refrigerator is a Model A and green if it is a model B.

[0056] The microprocessor device 140 then enters a continuously repeatedmain subroutine 206. Within each repetition of main subroutine 206,microprocessor device 140 updates its clock at step 208 and, once every18 hours, stores the time and water used in the non-volatile memory atstep 210. At steps 214 and 216, respectively, the amount of water usedis incremented if the ice valve 52 is open or if the fresh water valve54 is open. The open time for each valve 52 and 54 is weighted for thenormal water flow rate associated with the valve. At steps 216, 218 and220, respectively, the microprocessor calls the filter status subroutine250, the control subroutine 300 and the reset subroutine 350, afterwhich the main subroutine 206 repeats.

[0057] Referring to FIG. 6, the filter status subroutine 250 determinesat steps 252 and 254 whether refrigerator 10 is a model A, B or C anddirects the program to one of water usage comparison subroutines 256 a,256 b and 256 c, respectively for the appropriate model. In eachrespective water usage comparison subroutine 256 a, 256 b, and 256 c, atrespective steps 258 a, 258 b and 258 c, the status of the filter isdesignated as “good” if less than a first predetermined time period haspassed and less than a first predetermined quantity of water has beenconsumed, as indicated by the information stored in memory since thelast reset. In each respective water usage comparison subroutine 256 a,256 b, and 256 c, at respective steps 260 a, 260 b and 260 c, the statusof the filter is designated as “used” if more than a secondpredetermined time period of usage or more than a second predeterminedquantity of water has been consumed since the last reset. In eachrespective water usage comparison subroutine 256 a, 256 b, and 256 c, atrespective steps 262 a, 262 b and 262 c, the status of the filter isdesignated as “warn” if the status has been set as neither “good” or“used”.

[0058] Finally, at step 270, the time and water used is stored innon-volatile memory if the status of the filter has not been changed bythe water usage comparison subroutine 256 a, 256 b or 256 c. The statusis not restored if it hasn't changed so as to maximize the useful lifeof the EEPROM non-volatile memory.

[0059] Referring to FIG. 7, the control subroutine 300 determines atstep 302 if the fresh food door 20 is open by monitoring the voltageacross the fresh food light 24.

[0060] If the fresh food door 20 is detected as open, then indicatorsubroutine 310 is run. At step 312, the green LED die 134 is illuminatedif the status of the filter has been saved as “warn” or as “good”. Atstep 314, the red LED die 132 is illuminated if the status of the filterhas been saved as “warn” or as “used”. Thus, if the status has beensaved as “warn”, both LED die are alternatingly illuminated and thestatus indicator 66 appears amber in color.

[0061] The alternating signal of red and green is created by step 312always turning off the green die, off if it is on, and, after a built-intime delay by having step 314 always turn off the red die, if it is on.After a subsequent time delay, the programming again returns to step312, turning off the red LED and turning on the green LED.

[0062] If the fresh food door 20 is detected as closed, then diagnosticsubroutine 320 is run. At step 312, the green LED die is illuminated ifthe water dispenser valve 54 is open . At step 324, the red LED die isilluminated if the water valve 52 to the ice making apparatus 48 isopen. If both valves 52 and 54 are open, both LED die are illuminatedand the status indicator 66 appears amber. The diagnostic subroutine 320permits detection of malfunctions of the water valves 52 and 54 or thewater filter status monitoring and indicating system 70 by a servicetechnician manually by depressing the light switch 26 and selectivelyoperating the valves 52 or 54, the service technician can isolate faultsin the system.

[0063] Referring to FIG. 8, the reset subroutine 350 determines at step352 if the light switch 26 has been depressed 5 times in less than tenseconds, indicating the user is sending a reset instruction to themicroprocessor device 140. The user should do this when the filter isreplaced. If a reset instruction has been detected at step 352, then thetime and water usage counters are reset to zero at step 356 and storedto non-volatile memory at step 358. However, if the system has alreadybeen reset, within the last 10 seconds, that is, a reset instruction hasbeen sent twice, then, at step 354, the microprocessor device reads theinput as an instruction that a different type of filter is being usedand changes the model setting from a model A to a model B. Finally, atstep 360, the indicator is illuminated red or green to indicate themodel setting.

[0064] Operation of the Water Filter Status Monitoring & IndicatingSystem Components

[0065] The purpose of the water filter indicator is to provide theconsumer with a reliable measure of the filter cartridge end of lifecondition. There are two criteria for end of life, namely a prescribednumber of gallons or a fixed period of real time. In order to monitorthe water flow, the electrical inputs to both the ice maker valve andthe dispenser valve are monitored by the WFI. Since the processor“knows” that the valves have flow rates of 0.3 and 0.5 gallons perminute, the flow can be computed from the amount of time which each isenergized. It is in this fashion that the usage in gallons isaccumulated.

[0066] Real time is simply accumulated by a divider from the processorsclock. Since the clock used in this case is the internal RC oscillator,it is subject to more inaccuracy than would be experienced with acrystal controlled or 60 Hz based time keeping scheme. The Microchipliterature guarantees this tolerance to be about 7.0% over voltage andtemperature 4 variations. Also included in the microprocessor is anEEPROM device, which provides non-volatile retention of flow as well asreal time.

[0067] The state of the water filter is indicated on a bi-color LEDincorporating a red and a green die in the same package. By activatingboth die at a 50% duty cycle an amber color is obtained. Up to 90% lifethe indicator is green, from 90% to just less than 100% it is amber, andat end of life it shows red. User reset of the accumulated flow and timevariables is effected by activating the door switch five times within 5seconds.

[0068] In order to facilitate factory test as well as servicing in thefield, the LED displays usage status only when the door is open. Whenthe door is closed, the LED is off unless one or both of the valveinputs is active. The LED indicates red for the ice maker valve, greenfor the dispenser valve and amber if both valves are active.

[0069] The above constitutes a detailed description of the best mode ofthe present invention as contemplated by the inventors at the time offiling. It is further contemplated that changes and modifications may bemade from the best mode described herein within without departing fromthe spirit of the present invention or the intended scope of the claimsbelow.

1. in a refrigerator comprising an ice maker and a water dispenser, awater supply system for delivering filtered water from a water source tothe ice maker and water dispenser, the water supply system comprising: areplaceable water filter having an inlet for receiving water and anoutlet for outputting water such that water passing through the waterfilter from the inlet to the outlet is filtered; a water source conduitfor connecting the water source to the filter inlet to supply the waterfilter with water; a filtered-water conduit for connecting the filteroutlet to the ice maker and the water dispenser to supply the ice makerand water dispenser with filtered water; and a filter status unit fordetermining the status of the filter based on the filtered waterdemanded by the ice maker and water dispenser and comprising a watervolume meter for determining the volume of filtered water outputted bythe water filter for each demand of water, a filtered-water volumesumming device for maintaining an accumulated filtered-water volumebased on the filtered-water volume determined by the filtered-watervolume meter for each demand, and an indicator for signaling when theaccumulated filtered-water volume reaches a threshold value indicativeof the need to replace the water filter.
 2. The water supply systemaccording to claim 1 and further comprising a valve fluidly connected tothe filtered-water conduit for controlling the flow of filtered waterthrough the filtered-water conduit from the filter to one of the icemaker and water dispenser.
 3. The water supply system according to claim2 and further comprising a second valve fluidly connected to thefiltered-water conduit for controlling the flow of filtered waterthrough the filtered-water conduit from the filter to the other of theice maker and water dispenser.
 4. The water supply system according toclaim 3 wherein the filtered-water conduit comprises a first branch forconnecting to the ice maker and a second branch for connecting to thewater dispenser, and the valve is located in the first branch and thesecond valve is located in the second branch.
 5. The water supply systemaccording to claim 1 wherein the water volume meter comprises a timerfor determining the duration of each demand for water by either the icemaker or water dispenser and a data processor for calculating thefiltered-water volume for each demand based on the duration of eachdemand.
 6. The water supply system according to claim 5 wherein the dataprocessor comprises a memory in which is stored a flow rate for at leastone of the ice maker and water dispenser and the water volume for eachdemand is determined by the data processor calculating the product ofthe duration and the flow rate.
 7. The water supply system according toclaim 6 wherein the memory of the data processor stores a flow rate foreach of the ice maker and the water dispenser and the data processorselects the flow rate corresponding to which of the ice maker and waterdispenser is demanding filtered water when calculating thefiltered-water volume.
 8. The water supply system according to claim 7and further comprising a valve fluidly connected to the filtered-waterconduit for controlling the flow of filtered water through thefiltered-water conduit from the filter to one of the ice maker and waterdispenser.
 9. The water supply system according to claim 8 and furthercomprising a sensor for determining the opened/closed status of thevalve and coupled to the filter status unit for use in determining theduration of each demand for water.
 10. The water supply system accordingto claim 9 wherein the timer comprises a clock coupled to the dataprocessor, the sensor is coupled to the data processor, and the timerdetermines the duration of each demand of water by using the clock tomeasure the elapsed time that the valve is opened.
 11. The water supplysystem according to claim 10 and further comprising a second valvefluidly connected to the filtered-water conduit for controlling the flowof filtered water through the filtered-water conduit from the filter tothe other of the ice maker and water dispenser.
 12. The water supplysystem according to claim 11 and further comprising a second sensor fordetermining the opened/closed status of the second valve and coupled tothe filter status unit for use in determining the duration of eachdemand for water.
 13. The water supply system according to claim 12wherein the summing device comprises a portion of the memory in which isstored an accumulated filtered water value.
 14. The water supply systemaccording to claim 13 wherein the indicator comprises at least one of avisual and an audible indicator.
 15. The water supply system accordingto claim 14 wherein the indicator comprises a portion of the memory inwhich is stored a threshold value for the filter and the data processorfor comparing the accumulated filtered water value to the thresholdvalue to determine the status of the filter and activating the one ofthe visual and audible indicators when the filtered-water volume valuereaches the threshold value.
 16. The water supply system according toclaim 1 wherein the water volume meter comprises a sensor for detectingthe flow of filtered water from the filter, a timer for determining theduration of filtered water flow detected by the sensor, and a dataprocessor for calculating the volume of filtered water output from thefilter for the duration of the detected flow of filtered water.
 17. Thewater supply system according to claim 16 wherein the sensor comprisesan electrically actuated valve fluidly connected to the filtered-waterconduit for controlling the flow of filtered water through thefiltered-water conduit from the filter to one of the ice maker and waterdispenser and electrically coupled to the data processor and sending asignal to the data processor indicating the open/closed status of thevalve.
 18. The water supply system according to claim 17 wherein thetimer comprises a clock coupled to the data processor and determines theduration of the time that the valve is open.
 19. The water supply systemaccording to claim 18 wherein the sensor further comprises a secondelectrically actuated valve fluidly connected to the filtered-waterconduit for controlling the flow of filtered water through thefiltered-water conduit from the filter to the other of the ice maker andwater dispenser and electrically coupled to the data processor andsending a signal to the data processor indicating the open/closed statusof the second valve.
 20. A refrigerator comprising: a cabinet having afresh food compartment with an open face and a freezer compartment withan open face; a first door mounted to the cabinet for selectivelyclosing the open face of fresh food compartment; a second door mountedto the cabinet for selectively closing the open face of the freezercompartment; at least one water-using accessory; a replaceable waterfilter having an inlet adapted to fluidly connect to a supply ofhousehold water and an outlet fluidly connected to the at least onewater-using accessory; and; a filter status unit indicating thereplacement status for the replaceable water filter based on theaccumulated volume of filtered water supplied by the replaceable waterfilter.
 21. The refrigerator according to claim 20 wherein the at leastone water-using accessory is one of a water dispenser or an ice maker.22. The refrigerator according to claim 21 wherein the at least one of awater-using accessory is both the water dispenser and the ice maker. 23.The refrigerator according to claim 22 and further comprising a valvefluidly connecting at least one of the water dispenser and ice maker tothe replaceable filter.
 24. The refrigerator according to claim 23 andfurther comprising a second valve fluidly connecting the other of the atleast one of the water dispenser and ice maker to the replaceablefilter.
 25. The refrigerator according to claim 20 wherein the filterstatus unit further comprises a timer that determines the duration oftime that filtered water is supplied from the replaceable filter and afiltered-water volume calculator that calculates the filtered-watervolume based on the determined duration and the flow rate of thefiltered water to the at least one water-using accessory.
 26. Therefrigerator according to claim 25 wherein the timer determines aduration for each supply of filtered water to the at least onewater-using accessory, the filtered-water volume calculator calculates acorresponding filtered-water volume for each supply, and the filterstatus unit further comprises a filtered-water volume summing devicethat sums the calculated filtered-water volumes for each supply todetermine the accumulated volume of filtered water.
 27. The refrigeratoraccording to claim 26 wherein the filter status unit further comprises amicroprocessor having a memory and a clock coupled to the microprocessorand supplying timing data thereto, the microprocessor and the clock formthe timer to determine the duration of each supply, the microprocessorforms the filtered-water volume calculator by multiplying the durationby a flow rate stored in the memory, the microprocessor also forms thesumming device by calculating and storing in memory a valuecorresponding to the accumulated volume of filtered water.
 28. Therefrigerator according to claim 27 wherein the at least one water-usingaccessory comprises first and second water-using accessories.
 29. Therefrigerator according to claim 28 wherein the first water-usingaccessory has a first water flow rate, the second water-using accessoryhas a second flow rate, which is different than the first flow rate, andthe first and second flow rates are stored in the microprocessor memoryand the microprocessor selects the flow rate corresponding to which ofthe first and second accessories is supplied filtered water by thefilter when calculating the water volume supplied by the replaceablefilter
 30. The refrigerator according to claim 29 and the filter statusunit further comprises a sensor for determining which of the first andsecond accessories is being supplied water from the water filter. 31.The refrigerator according to claim 30 wherein the sensor comprises atleast one valve fluidly connecting one of the first and secondaccessories to the replaceable filter and the at least one valve iscoupled to the microprocessor and provides a signal to themicroprocessor indicative of when the at least one valve is open. 32.The refrigerator according to claim 31 wherein the sensor comprises asecond valve fluidly connecting the other of the first and secondaccessories to the replaceable filter and the second valve is coupled tothe microprocessor and provides a signal to the microprocessorindicative of when the second valve is open.
 33. In a refrigeratorcomprising at least one water-using accessory with a replaceable filtercoupled to a water supply and a water supply system for deliveringfiltered water from the replaceable filter to the at least onewater-using accessory, a filter status unit for determining whether thereplaceable filter should be replaced, the filter status unitcomprising: a timer that determines the duration of time that filteredwater is supplied from the replaceable filter to the at least onewater-using appliance; a filtered-water volume calculator thatcalculates the filtered-water volume based on the determined durationand the flow rate of the filtered water to the at least one water-usingaccessory; and a filtered-water volume summing device for maintaining anaccumulated filtered-water volume based on the calculated filtered-watervolume.
 34. The filter status unit according to claim 33 wherein thetimer determines a duration for each supply of filtered water to the atleast one water-using accessory, the filtered-water volume calculatorcalculates a corresponding filtered-water volume for each supply. 35.The filter status unit according to claim 34 wherein the filtered-watervolume summing device sums the calculated filtered-water volumes foreach supply to determine the accumulated volume of filtered-water. 36.The filter status unit according to claim 35 and further comprises amicroprocessor having a memory and a clock coupled to the microprocessorand supplying timing data thereto, the microprocessor and the clock formthe timer to determine the duration of each supply, the microprocessorforms the filtered-water volume calculator by multiplying the durationby a flow rate stored in the memory, the microprocessor also forms thesumming device by calculating and storing in memory a valuecorresponding to the accumulated volume of filtered water.
 37. Thefilter status unit according to claim 36 wherein the flow rate isapproximately equal to the rate at which the at least one water-usingappliance draws the filtered water.
 38. The filter status unit accordingto claim 36 wherein the at least one water-using accessory comprisesfirst and second water-using accessories.
 39. The filter status unitaccording to claim 28 wherein the first water-using accessory has afirst water flow rate, the second water-using accessory has a secondflow rate, which is different than the first flow rate, and the firstand second flow rates are stored in the microprocessor memory and themicroprocessor selects the flow rate corresponding to which of the firstand second accessories is supplied filtered water by the filter whencalculating the water volume supplied by the replaceable filter.
 40. Thefilter status unit according to claim 39 wherein the filter status unitfurther comprises a sensor for determining which of the first and secondaccessories is being supplied water from the water filter.
 41. Thefilter status unit according to claim 40 wherein the sensor comprises atleast one valve for fluidly connecting one of the first and secondaccessories to the replaceable filter and the at least one valve iscoupled to the microprocessor and provides a signal to themicroprocessor indicative of when the at least one valve is open for useby the microprocessor in determining the duration of the supply.
 42. Thefilter status unit according to claim 41 wherein the sensor furthercomprises a second valve fluidly connecting the other of the first andsecond accessories to the replaceable filter and the second valve iscoupled to the microprocessor and provides a signal to themicroprocessor indicative of when the second valve is open for use bythe microprocessor in determining the duration of the supply.
 43. Thefilter status unit according to claim 36 and further comprising anindicator that sends a signal observable by a user that the replaceablefilter needs replacing.
 44. The filter status unit according to claim 43wherein the indicator comprises at least one of a visual and an audibleindicator.
 45. The filter status unit according to claim 44 wherein theindicator comprises a portion of the memory in which is stored athreshold value for the filter and the microprocessor compares theaccumulated filtered water value to the threshold value to determine thestatus of the filter and activates the at least one of the visual andaudible indicators when the filtered-water volume value reaches thethreshold value.